Immediate Effects of an Inverted Body Position on Energy Expenditure and Blood Lactate Removal after Intense Running

We compared the immediate effects of a cool-down strategy including an inverted body position (IBP: continuous 30-s alternations of supine and IBP) after a short period of an intense treadmill run with active (walking) and passive (seated) methods. Fifteen healthy subjects (22 years, 172 cm, 67 kg) completed three cool-down conditions (in a counterbalanced order) followed by a 5-min static stretch on three separate days. Heart rate, energy expenditure, blood lactate concentration, fatigue perception, and circumference of thighs and calves were recorded at pre- and post-run at 0, 5, 10, 20, and 30 min. At 5 min post-run, subjects performing the IBP condition showed (1) a 22% slower heart rate (p < 0.0001, ES = 2.52) and 14% lower energy expenditure (p = 0.01, ES = 0.48) than in the active condition, and (2) a 23% lower blood lactate than in the passive condition (p = 0.001, ES = 0.82). Fatigue perception and circumferences of thighs and calves did not differ between the conditions at any time point (F10,238 < 0.96, p < 0.99 for all tests). IBP appears to produce an effect similar to that of an active cool-down in blood lactate removal with less energy expenditure. This cool-down strategy is recommended for tournament sporting events with short breaks between matches, such as Taekwondo, Judo, and wrestling.

Non-oxidative Energy Supply Correlates with Lactate Transport and Removal in Trained Rowers

This study aimed to test if the non-oxidative energy supply (estimated by the accumulated oxygen deficit) is associated with an index of muscle lactate accumulation during exercise, muscle monocarboxylate transporter content and the lactate removal ability during recovery in well-trained rowers. Seventeen rowers completed a 3-min all-out exercise on rowing ergometer to estimate the accumulated oxygen deficit. Blood lactate samples were collected during the subsequent passive recovery to assess individual blood lactate curves, which were fitted to the bi-exponential time function: La(t)= [La](0)+A1·(1–e–γ 1 t)+A2·(1–e–γ 2 t), where the velocity constants γ1 and γ2 (min–1) denote the lactate exchange and removal abilities during recovery, respectively. The accumulated oxygen deficit was correlated with the net amount of lactate released from the previously active muscles (r =0.58, P<0.05), the monocarboxylate transporters MCT1 and MCT4 (r=0.63, P<0.05) and γ2 (r=0.55, P<0.05). γ2 and the lactate release rate at exercise completion were negatively correlated with citrate synthase activity. These findings suggest that the capacity to supply non-oxidative energy during supramaximal rowing exercise is associated with muscle lactate accumulation and transport, as well as lactate removal ability.

Cardiometabolic Recovery and Lactate Removal may be Related to Muscular Adaptations

The aim of this study was to measure the differences in cardiorespiratory recovery (CR) and blood lactate removal among young athletes with differences in non-lactic (NP) and lactic anaerobic power (LP) and fatigue index (FI) but with the same degree of cardiorespiratory fitness. Sixteen swimmers from the Brazilian synchronized swimming team (2014) were divided into two groups GAP (Group High Power) (n = 9), with NP, LP, and FI (p<0.05) compared to GBP (Group Low Power) (n=7). Both groups performed a four-minute routine at competitive intensity. Anaerobic power, maximal heart rate (HR) and blood lactate (BL) were determined before and at 1, 3 and 5 minutes after the routine. Student’s t-test was used to analyze the intergroup differences of NP, LP, FI, maximum and lactic HR, and two-way ANOVA followed by Bonferroni was used to analyze HR and BL at 1, 3 and 5 minutes after activity with a significance of 5%. The FI of the GBP group was lower than that of the GAP group (P <0.05). The NP of the GBP group was higher than that of the GAP group (P <0.05). The maximum HR of the GBP group was equal to that of the GAP group (P> 0.05). The GBP group had better HR recovery than did the GAP group (P <0.05). BL had its lowest levels after 1 and 5 minutes of recovery in the GBP group when compared to the GAP group (P <0.05). The GBP group’s FI was significantly lower than that of the GAP group, while NP was higher, and CR was better in the GBP group, indicating a relationship between a lower FI and higher NP and LP with CR and suggesting that muscular adaptations have an important influence on CR and BL removal.